Ozone: Bad for Trees, Good for What Eats Them
The trees of the future may be much more vulnerable to a variety of pests, say scientists studying greenhouse gases in northern Wisconsin forests. Their work was published this year in the journal Nature.
Researchers in the Aspen FACE (Free-Air Carbon dioxide Enrichment) Experiment, led by scientists at Michigan Tech and the U.S. Forest Service, have been measuring the effects of elevated levels two greenhouse gases, carbon dioxide and ozone, on aspen forest ecosystems.
While the trees seem to do relatively well in a carbon dioxide-rich atmosphere, ozone is another story. Trees (Populous tremuloides—or trembling aspen) growing in an ozone-enriched atmosphere have been hit much harder by their traditional enemies: forest tent caterpillars, aphids and the rust fungus Melampsora.
“This has been a surprise,” said FACE director David Karnosky of Michigan Tech’s School of Forest Resources and Environmental Science. “Our experiment was never meant to look at pest occurrence. But it became obvious that the greenhouse gases were affecting the abundance of pests.”
Aphids thrive in high-ozone air and populations of the tiny insects’ traditional predators—such as ladybugs and spiders—plummeted.
The number of aphids increased about five-fold in plots with elevated ozone, while the number of aphid predators was cut in half. In plots with elevated levels of both carbon dioxide and ozone, the aphid population tripled, while the number of natural enemies increased slightly, mitigating the aphids’ effect on the aspen.
Studies have shed some light on why the aspen growing in ozone-rich air were turning into so much bug salad: their leaves seem to be undergoing fundamental changes. “Ozone alters the surface waxes,” said Kevin Percy, a research scientist with Natural Resources Canada—Canadian Forest Service.
Melampsora infection in the control and CO2-enriched plots was about the same, but increased about 400 percent in the O3 plots and doubled in the plots with extra CO2 and O3. The number of forest tent caterpillars increased by about one-third in the O3 plots and actually decreased slightly in the CO2 plots and the plots with extra CO2 and ozone.
The Aspen FACE Experiment, which involves 11 institutions and 28 researchers, is funded jointly by the Department of Energy’s Office of Biological and Environmental Research, the National Science Foundation, the U.S. Forest Service Global Change Program, the U.S. Forest Service North Central Research Station, Michigan Tech, the USDA National Research Initiative Program, Brookhaven National Laboratory and Natural Resources Canada. The FACE system was designed by George Hendrey and his Brookhaven National Lab team.
Professor Kurt Pregitzer, another FACE Experiment researcher from Michigan Tech, calls Aspen FACE “a window into the future.”
“We’re beginning to understand how the changing atmosphere of the Earth is going to impact forests and the interactions that control the growth of trees, the cycling of energy and nutrients, and the movement of water through ecosystems,” he said.
“This particular paper points out how important understanding the interactions among plants and insects are in controlling forest growth and forest health.
“We have a lot to learn.”
Humanities Prof Earns Teaching Award
Heidi Bostic's research interests have resulted in an award for teaching. The assistant professor of French at Michigan Tech earned a national teaching award from the American Society for Eighteenth Century Studies.
While a teacher of French language, Bostic also teaches 18th century literature and does research in the area of gender theory.
Her award-winning course description, for example, is "Gender and Society in Eighteenth Century France."
"We look at ways in which gender influenced the period's cultural practices," she said.
"Eighteenth century thinkers tended to believe that women lacked reason but had extreme sensibility, yet her place was in the home. This created a tension with that century's proclamations of universal liberty and equality."
Bostic's course is part of a seminar with the main theme of "individual and society."
"We also study the roles of women and men during the French revolution, using literary texts," she said. "We read texts by women and about women. In general, gender theory means looking at the situation of women in the world. We investigate categories we take for granted, but that may turn out to have a gender bias.
"As a very basic example, a study of a major research university found that more lab space went to men than women. The situation was corrected, but the point is that this does happen."
Times Square Changes Explored in New Book
Once a seedy New York porno and prostitution district, it now features stores and offices of some of America’s largest companies.
You will find Viacom’s MTV studios, ESPNZone, many chain stores and restaurants, and the CondeNast skyscraper with a giant eight-story cylindrical video screen.
That’s good and bad, says Daniel Makagon, a Michigan Tech faculty member who has written a book about the change, “Vibrating Streets: Times Square and the Urban Dream.” Makagon is an assistant professor of communication and cultural studies in Tech’s humanities department.
The book looks at the “Disneyfication” of Times Square to an entertainment and business district.
“Disney bought the New Amsterdam Theater in 1993 and things began to change,” Makagon says. “There are fewer independently owned shops. There are a lot of chain stores and restaurants. It flattens out Times Square’s unique character. And it tells people that transformation can only happen with big companies and big money.”
Starting in mid-1999, Makagon interviewed a range of people: political leaders, theater people, street musicians, and senior citizens at a church luncheon.
“One nice thing about ethnographic work is that you spend time in the place and talk with the people,” he said. “For example, I found that women feel safer now in Times Square than they did in the 1970s. Senior citizens feel good about going there. That is a very positive change. When people feel safe, that’s a good thing.”
With mega-companies and big money driving the change, however, the character of this unique urban space has changed. “Times Square is an exciting place,” he says. “At the same time, there are some problems with the way the revitalization has occurred. Other options—such as civic groups, artists, and local people trying to do something internally—were basically ignored by various mayors.
“Disney put a lot of money into expensive productions like Beauty and the Beast and the Lion King. Shows have become so expensive that they cater only to the upper middle class. Some of the second run movie houses and relatively inexpensive theaters are gone, removing entertainment options for working class families.”
Reinvigoration from local groups, he believes, would have resulted in a different kind of transformation.
“I think people want something that is real,” he says. “They want an element of chaos in their lives. That’s part of living in a city—a sense of chance.”
“Vibrating Streets” will be available later this year.